Weltschmerz, German for "world pain," was coined during the Romantic Era by the German author Jean Paul (Leben des Vergnügten Schumeisterlein Maria Wutz in Auenthal - 1790) and is in many ways the German version of your fancy French ennui. It describes a world weariness felt from a perceived mismatch between the ideal image of how the world should be, with how it really is. In German philosophy it was distinguished from pessimism, the idea that there is more bad than good in the world, because while pessimism was the logical conclusion of cool rational philosophical pondering, weltschmerz was an emotional response. Though weltschmerz and ennui are fairly close synonyms, ennui foregrounds the listlessness brought on by world weariness (it can also be a term for more simple boredom), and weltschmerz foregrounds the pain or sadness. There is mayhap a greater sense of yearning in weltschmerz (part of the pain is that the sufferer really wants the world to be otherwise). Also, when used in English, weltschmerz is not as common as ennui, so there are fewer connotations regarding the type of person that comes down with it. On the face of it, it is far more Germanically grim, than that French ennui.
Do you have sadness in your heart for the world that can never be, and wear sensible shoes... possibly Loakes? Well that my friend is weltschmerz.
